An "assistantship" is a position in which someone helps or supports someone else in their work or tasks. It is like being an assistant or a helper to someone.
Weissberg and UIC collaborators secure funding to provide research assistantships for graduate students to help advance the science of social and emotional learning. (novofoundation.org)
AF: This semester you are Artist in Residence with a Teaching Assistantship at New York Studio Residency Program (NYSRP). (artefuse.com)
Graduate assistantships in Teaching and Learning programs involve: (education.uiowa.edu)